_ProjectionParams.z is not equal to camera.farClipPlane!

Unity Engine
1

I’m quite confused about this. I’m implementing log depth buffer. It works fine with far clip plane distance from _ProjectionParams.z, but is different when it comes from camera.farClipPlane and is passed by me manually.
_ProjectionParams.z varies heavily when there’s a big difference between the near and far plane, especially with very low near plane distances. The variation looks random, so my guess is it’s because of precision artifacts.

So on one hand, there is a value that is not numerically correct, but works, and then there’s a value that doesn’t, but seems exact. The reason I want to pass it myself is because I’m using it in operations that are constant, so I want to move the load to CPU and pass the final values

My question is, is there a way to get a value that’s equal to _ProjectionParams.z in a script?

2

Problem solved! I figured it might be computing it from the projection matrix, so that’s what I did. The computed far plane distance is inaccurate → it works perfectly!

float farPlane = camera.projectionMatrix.m23 / (camera.projectionMatrix.m22 + 1);
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